Producing colored light beams from white light

Abstract

A color-separating prism includes first, second, and third component prisms that form first and second adjacent pairs of faces and include nonadjacent faces. The third component prism has a front surface or face. The color-separating prism includes a first reflective layer disposed in part between the first adjacent pair of faces and in part on one nonadjacent face and a second reflective layer disposed in part between the second adjacent pair of faces and in part on another nonadjacent face. The first and second reflective layers are inclined to reflect portions of light incident on the front surface back toward the front surface for total internal reflection. The color-separating may be used to produce narrow-spectral light from broader spectral light. A first portion of a light beam substantially in a first wavelength range is reflected from the first reflective layer back toward the front face of the prism. A second portion of the light beam substantially in a second wavelength range is reflected from the second reflective layer back toward the front face of the prism. The first and second portions are totally internally reflected from the front face. The color-separating prism can be used in display systems.

Description

1. Field of the InventionThe present invention relates generally to optical devices and prisms, and, more particularly, to separating a white light beam into several colored light beams.2. Description of the Related ArtFIG. 1 illustrates a color-separating prism based on a cross cube 10. The cross cube 10 has a square cross section and is composed of four glass prisms 12, 14, 16, 18. A first reflective layer 20 lies along a first principal diagonal of the cross cube 10. A second reflective layer 22 lies along a second principal diagonal, and intersects the first layer 20 at a right angle. The first and second reflective layers 20, 22 are multi-layers of dichroic material that selectively reflect certain wavelength or color ranges of light.Referring to FIG. 1, a white light beam 24 enters the cross cube 10 through a first face 26 and is selectively reflected by the first and second reflective layers 20, 22. The first reflective layer 20 reflects red light 28 from the incoming white l...

AI Technical Summary

Problems solved by technology

Moreover, for the cross cube 10, another disadvantage is that the center of the "X" may be projected (e.g., in a projection system) to a screen and seen as a line to a viewer of the screen.

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